#include <iostream>
#include <string>
using namespace std;

class Time {
public:
    void set_time();
    void show_time();
private:
    int hour;
    int minute;
    int second;
};

class Student {
public:
    void display();
    void set_value();
private:
    int num;
    string name;
    char sex;
};

class Box {
public:
    void set_item();
    int get_volume();
    void comp_volume();
private:
    int len;
    int width;
    int high;
    int volume;
};